Integrated circuit design is constantly being scaled down in pursuit of faster circuit operation and lower power consumption.
As semiconductor devices become smaller there is a need for higher dielectric constant (high-k) gate material.
Many high dielectric constant dielectric materials (high-k dielectric) have been investigated as possible replacements for silicon dioxide, which is the material of choice for the gate electrode. But one of the remaining problems is the deposition of the high-k materials on substrate surfaces for obtaining layer thickness compatible with the properties and applications sought.
WO02/43115 describes a method for treating substrate surfaces in preparation for subsequent nucleation-sensitive depositions and adsorption-driven deposition by means of non-depositing plasma products.
U.S. Pat. No. 6,620,720 describes a method for reducing the thermal budget in a semiconductor manufacturing process wherein the remote thermal nitridation step is replaced by a remote plasma nitridation step.
None of these methods allows the formation of a smooth, uniform and closed film (or layer) upon chemically stable substrate surfaces.
Indeed, up to the present invention, deposition of a high-k metal oxide on a chemically stable surface started slowly and through the local nucleation of three dimensional (higher than one monolayer) islands distributed all over the surface. Films closure took place only once the islands were big enough to grow together. Consequently, a certain minimum thickness of material had to be deposited before obtaining a closed film to be used for semiconductor applications (e.g. about 10 nm or more).